Manufacture of acetyl-cellulose solutions.



I 1,095,999. Ro mawing.

TED STATES PATENT OFF CE. v

m E. REID, or ROCHESTER, NEW-roan, ASSIGNOR .TO EASTMAN KODAK aocnnsrna,NEW roan, A coaronarron or NEWYORK.

To all them it man concern: Be it known that I, DAVID E. Barn,Rochester, in the county of Monroe and State of New York, have inventedcertain -:new and useful Improvements in the Manufacture ofAcet-vl-Cellulose Solutions; and

II do hereby declare the following to be a face and allowing the solventto volatilize or Y full, clear, and exact description of the same.

My invention relates to the manufacture of relatively thin transparentsheets of acetyl cellulose of varying thickness suitable for supportsfor photographic film and for other purposes for which transparentflexible sheets are desirable The most desirable -manner of formingsheets of this character is by flowing a thick solution of the materialupon a support having a polished surevaporate, but difficulties areliable to arise by reason of the too rapid volatilization of the solventemployed and it is, therefore,

. the object of my invention to incorporate have with the solvent amaterial which is not a solvent. of acetyl cellulose but will, in ameasure, retard the evaporation of the solvent during the formation ofthe sheet, and is necessarily of such nature that it will not anappreciably deleterious effect upon the product when used for itsintended sheets unsuitable for such purposes, as, for

instance, a support for photographic film. When these sheets are used assupports for photographic films, it is desirable and necessary that theretarding material used with the solvent have certain characteristics,as for instance: First: 'It must be of such a nature that it will notinjuriously affect-or interfere with the application of the sensitizedcoating. Second: It must-have a'relatively high boiling point, ascompared with that of the solvent, in order that. the sheet will cureout slowly and evenly. Third: It must be of such a nature that nochemical reaction will take place between it and the solvent or thecellulose: Fourth: It shall Specification of Letters Patent. Applicationfiled July 6, 1909. Serial No. 505,978.

have no effect upon the solvent or the celluparen'cy of the product.

uniform thickness,- is free from pits or lines .the same remains in thecompleted product Patented Ma 5, 1914.

lose to render it turbid or affect the trans- Fifth: It must have nochemical reaction with or on the ordinary metals. Sixth-2 It must not ofit self be inflammable and must not increase 6 the inflammabilityof'acetyl cellulose, and seventh: It'must not be ol'eaginous incharacter, as otherwise the surface of the sheet would be renderedobjectionable for further treatment or the application of othermaterials. After considerable experimentation and research, I havediscovered a material having these characteristics in pentachlorethane,one of the chlorin derivatives of ethane, having the formula C HCI and aboiling point of 150 C. v

In carrying out my invention I first dissolve the acetyl cellulose in asuitable solvent having a low boiling oint, such as acetone orchloroform, in t e proportion of about one part'of cellulose to four ofacetone.

or the other solvent, and to this add an 5 amount of pentachloreth'aneequal to 50 to per cent. of the weight of cellulose, and

thoroughly incorporate thesame by agitation. This thick viscous solutionis then filtered and is coated in a'--thin coating upon a suitablesupport, and after drying'or setting by the volatilization of thesolvent it is stripped or removed for use; The action of thepentachlorethane retards the vola tilization of the acetone j or solventto such an extent that the sheet is transparent, of

and irrg.ularities,.and its surface is smooth and of such nature thatthe'sheets may be used for any purpose.

It will be noted that pehtachlorethane havinga high boiling point,.aproportion of 95 from which the low boiling point solvent, as. acetoneis eliminated by volatillzation,

and that the thin sheets formed as described are flexible, transparent,not readily inflammable, and are desirable as supports for a sensitizedcoating for photographic purposes, neither the coating nor the sheetbeing afl'ected by the materials employed.

I claim as my invention:

1. A flowing solution of acetyl cellulose in a solvent having a lowboiling point and containing a transparent liquid which is a non-solventof cellulose, possessing a rela' tively high boiling point, which isnonoleaginous in character and does not enter into chemical combinationwith the cellulose or the solvent employed, is not of itself inflammable and does not increase the inflammability of acetyl cellulose.

2. The flowing solution of acetyl cellulose in acetone containingpentachlorethane lution of acetylcelluose in pentachlorethane andorganic solvents.

5. As a new composition of matter a solution of cellulose esters inpentachlorethane and acetone.

6. As a new composition of matter-a solution of acetylcellulose inpentachlorethane and acetone.

7. A composition of matter comprising acetyl cellulose containingpentachlorethane.

8. As a new composition of matter, a cellulose ester containinpentachlorethane.

9. As an article 0 manufacture, a sheet of deposited or flowed aoetylcellulose containing pentachlorethane. v

DAVID E. REID.

Witnesses:

GEO. EASTMAN: ALICE K. WHITNEY.

